Blunted vascular responses but preserved endothelial vasodilation after submaximal exercise in chronic heart failure.

BACKGROUND: Patients with chronic heart failure (CHF) have abnormal vascular responses to acute exercise; however, regular aerobic training improves endothelial function in these patients. We hypothesized that, because of their attenuated vascular responses, CHF patients would present abnormal endothelium-dependent vasodilatation after a single exercise session.

METHODS: Thirteen CHF patients and 13 healthy controls participated in two experiments, on different days, using a cross-over design: (i) control (25-min seated at rest), and (ii) a submaximal exercise session (25-min cycling). Measurements of heart rate, blood pressure (BP), venous occlusion plethysmography forearm blood flow (FBF), and reactive hyperemia were made before and after (immediately, 10, 30, 60 min, and 24 h) each experimental condition.

RESULTS: CHF patients had no changes in the mean BP throughout the protocols, whereas mean BP was reduced up to 60 min after exercise in controls. In CHF patients, FBF was increased and forearm vascular resistance was reduced up to 10 min after exercise, whereas these changes were sustained up to 30 min after exercise in controls. Reactive hyperemia was significantly increased up to 30 min after exercise in both groups.

CONCLUSION: Patients with CHF have increased postexercise FBF and decreased forearm vascular resistance; however, these responses last longer in healthy individuals. Despite the attenuated postexercise vascular responses, patients with CHF respond to a single-cycle exercise session with improved forearm endothelium-dependent vasodilation.